Multipurpose overhead lines protection algorithm

A numerical algorithm for multipurpose overhead lines protection, based on one terminal data and derived in the time domain, is presented. The fault location, direction and its nature (arcing or arcless fault) are estimated using the least squares error technique. The faulted phase voltage is modelled as a serial connection of fault resistance and are voltage, offering more sophisticated line protection. The algorithm can be applied to both the ordinary and high-impedance fault detection, distance protection, intelligent autoreclosure, as well as for directional relaying. The new approach does not require the line zero-sequence resistance as an input datum. The algorithm is derived for the case of most frequent single-phase-to-ground asymmetrical faults. The results of algorithm testing through computer simulation are given. The influence of remote infeed, fault resistance, higher-order harmonics, power system frequency, network topology, line parameters and other factors are investigated and systematically presented.